Apparatus and process for making filaments



May l0, 1949. E. E; LovlG 2,470,039

APPARATUS AND `PROCESS FOR MAKING FILMENTS Filed May 4, 1945 4 Sheets-Sheet 1 E. E. LOVIG APPARATUS AND PROCESS FOR MAKING FILAMENTS May l0, 1949.

4 Sheets-Sheet 2 Filed May 4, 1945 S mwm www May 10, 1949. E. E. LovlG 2,470,039

APPARATUS AND PROCESS FOR MAKING FILMENTS Filed may 4, 1945 4 sneets-sheet 5 z3 l D. F 4 260 32 zz 94 L 212 Sz as azi 90 aa ao 3,6 A 3' 6J fzs n' ze 'F ,lez

tu 0 c 44 Inventor Edward E. #444 M May 10, 1949 E. E. LovlG 2,470,039

APPARATUS AND PRGCESS FOR MAKING -FILAMEN'I'S Filed llay 4, 4 Sheets-Sheet 4 INVENTOR. Edward E Patented May 10, 1949 APPARATUS AND PROCESS FOR MAKING FILAIVIENTS Edward E. Lovlg, Chicago, Ill.

Application May 4, 1945, Serial No. 591,904

10 Claims.

This invention relates to novel laments and their manufacture.

It is an object of my invention to produce a synthetic filament which, when placed alongside and together with like filaments, will interlock therewith so that a number of strands or the same continuous piece of lament may be collected and hunched together to form a product which is substantially shape retaining and resilient and can be used for liquid and gas filtering, heat insulation, padding, and other purposes.

A further object is to provide novel apparatuses and processes for producing any one or more types of laments having these characteristics.

It is also an object of my invention to provide a lament which ls kinked at relatively short intervals throughout the length thereof.

Another object is to provide a filament which is kinked at irregular intervals throughout the length thereof.

Further objects and advantages of my invention will appear as the description proceeds.

The invention will be better understood upon reference to .the following description and the accompanying drawings, in which:

Fig. l is a side perspective view of an apparatus constructed in accordance with my invention.

Fig. 2 is an opposite side yand top perspective view of the same.

Fig. 3 is an enlargement of a portion of Fig. 2.

Fig. 4 is a front perspective view of the complete structure.

Fig. 5 is a longitudinal diagrammatic sectional view of the same.

Fig. 6 is an enlarged elevational view of a traction roller and associated mechanism.

Fig. 7 is a view. partly in section, and magnified about thirty times, of a portion of a filament according to my invention.

Fig. 8 is a diagrammatic view of an electrically heated crimp roller according to my invention.

Fig. 9 shows in single line form a portion of a filament after it has been crimped but before being kinked.

Fig. 10 shows in single line form a portion of a filament after it has been crimped and kinked.

In the manufacture of air filters, it has been the custom to use hair, sisal grass, sisal hemp, Tampico hemp, wire and other materials. Hair is resilient and does not pack excessively and can be curled so that when used as a filter and in proper lengths it is fairly eillcient. However, it is smooth and hence oil does not adhere to it very well and particles in the air slip by. Moreover hair is quite expensive and is scarce in lengths suiliciently great to be efficient. Sisal grass, sisal hemp and Tampico hemp are quite still and smooth and require expensive processim and come in shorter lengths than desired. Wire has been found no more eillcient than hair. Other materials have been used but they have been found unsatisfactory for various reasons.

I have discovered that a filament can be made which can -be used as a filter material and for other purposes, of which those noted above are examples, and, when so used, is more emclent and much less expensive than materials heretofore used for such purposes. My invention embraces not only a novel iilament but also unique apparatuses and processes for making the lament in various forms according to the uses to which itis to be put.

In practicing one form of my invention, I start with a strand consisting entirely of vegetable fiber of substantial cellulose content, of which cotton is an example, or of a mixture of cellulose with a synthetic ber, of which examples are rayon and nylon. A filament which is to be used as an air filter, for example, should :be resilient, among other things. Increasing the number oi' plies with the same tightness of twist increases its resilience but the cost is also greatly increased. Increasing the tightness of twist or spin with the same number of plies increases the resilience but decreases the yardage per unit weight. If I start with a loosely spun single-ply mixture of approximately equal parts of cotton and synthetic fiber. I can obtain the same yardage and resilience as is obtainable with a triple-'ply tightly spun allcotton strand at about one-half the cost at present day prices. Such a, mixture may be spun loosely but enough to hold the bers together so that there will be sufilcientstrength inthe composite strand to withstand the pulls to which it will be subjected in the process of making the lament to which this invention relates. This composite material, as noted above, is very much cheaper than an al1-cotton material, for the same end results. One reason for this is that the synthetic fiber has the property of imparting resilience to the finished product, and thus obviates the cost of spinning operations inherent in multiple-ply strands. The percentage of synthetic fiber, the tightness of twist and the number of plies of the mixture strand may be varied as desired according to the purpose of the ilnished product. The strand could be all cotton or all synthetic cellulose-containing tlber in various tightnesses of twist and various numbers of plies. according to the treatment to be given it and the 3 purpose of the product into which it is to be made.

In one form of my invention, in which I start with a. cellulose-containing strand, I prefer to employ a single or multiple-ply strand consisting entirely of vegetable ber, such as cotton, or a mixture thereof with one or more synthetic fibers such as, but not limited to, rayon. nylon, or glass.

An apparatus for carrying out one form of my invention is shown for illustrative purposes in the accompanying drawings. Any number of filaments may be processed simultaneously, and, accordingly, I may provide one or more spools 28, only one being illustrated for the sake o1' simplicity. Accordingly the various rollers hereinafter referred to may be formed to accommodate the desired number of strands simultaneously. For initially guiding the strands 2| I may provide banks of guide eyes 22, 23, from the latter of which the strands, of which only one ls shown for simplicity, pass down under and in grooves of a grooved roller 26, which is held against racing as by a brake spring 21, made of wire or otherwise, and anchored to a bracket 28 extending from the roller-carrying axle 29, the spring bearing frictionally against the roller. The grooves 25 hold the various strands 2| apart. From this grooved roller 25 the strand passes about a friction or traction roller 32 supported by and at one end oi' an acid-resistant tank 36 containing an acid having the property of converting cellulose to a gelatinous state, for example a weak sulphuric acid solution 38 which may be cold or at room temperature and may consist of two parts of commercial sulphuric acid (which is generally about 97% of full strength) to one part of water by volume. The tank may be leadlined. Then the strand passes under and in a groove of a grooved roller 42 disposed over the surface 43 of the acid. 'I'he grooved roller 42 and traction roller 32 are preferably geared together as at 48, the arrangement being such that the linear speed of the strand-engaging portions of the rollers 32 and 42 will be the same and therefore the grooved roller 42 will not add to the tension on the strand and both rollers will carry the strand and thus act as a conveyor. The strand passes down from the grooved roller 42 and under and in contact with a grooved roller 58 immersed in said solution, runs to a second immersed grooved roller 52, and then rises out of the solution and passes about a grooved roller 54 preferably disposed over the surface of the solution, the grooved rollers being acid-resistant and preferably of light weight to reduce resistance to turning. From the grooved roller 54 the strand passes over a second traction roller 55, preferably clear of the acid tank 36 and geared to the roller 54 as at 58, then, if desired, over a grooved guide roller 51 to insure against wrapping of the strand about the second traction roller 55, which might otherwise occur if the tension on the strand is low or the speed of the strand is high. In other cases the roller 51 could be omitted, in which event the strand may pass from the traction roller 55 directly to the tank therebelow. Then the strand passes down outside oi' the acid tank 38 and into a second tank 58 containing preferably circulating water 58, which may be cold, for rinsing the acid-treated strand, the water being supplied at 88 and discharged at 6|., The strand then passes under a grooved roller 52 immersed in the water and runs under a second immersed grooved roller 84 from which it passes to a grooved roller 86 disposed outside of the water. From the grooved roller I8 the strand passes about a third traction roller 8l. these rollers being preferably geared together as at 48.

The acid tank 38 may have a drain plug Bil-arranged over the water tank 58 from which the circulating water discharges to sewerage.

Before the strand is treated it is dry and will stand more tension than when in the acid bath. When treated by the acid, care must be taken to avoid undue pulling of the strand. If there were no traction by the first traction roller 32, the strand would be under direct tension between the spool 20 and the second traction roller 55. and the resistance oiered by the spool and other parts before the strand reaches the rst traction roller 32 might be sufficient to strain the part of the strand in the acid excessively and cause it to weaken or break. By providing traction (by means hereinafter described) at the first traction roller 32, which, as pointed out above. cooperates with the grooved roller 42 to serve as a conveyor, and by driving the second traction roller 55 at a surface speed no greater than that of the irst traction roller 32, they cannot tension the portion of the strand in the acid, and thus the whole system of rollers from the ilrst traction roller 32 to the second traction roller 55 acts as a conveyor. In practice, to obviate the necessity for precision manufacture, it may be advisable to construct the parts so that the surface speed of the second traction roller 55 is definitely less than that of the ilrst traction roller 32. In such event provision should be made for slippage of the strand past the second traction roller 55, as will appear.

The third traction roller 88 should preferably be synchronized with the first traction roller 32, in which event there would be a slight slippage of the strand over the second traction roller 55. If the third traction roller 83 runs somewhat faster than the rst traction roller 32, there will be some slippage of the third traction roller past the strand, tending to increase the tension somewhat. This may not be harmful for strong strands but may be undesirable for weak strands such as yarns, for example. Where the strength of the strand material permits, it may be advisable to run the third traction roller 68 slightly faster than the first traction roller 32, since precision manufacture is thereby obviated. 'I'he third traction roller 88 preferably does not run slower than the i'lrst, since the strand may accumulate therebetween, or, if a succeeding traction roller runs fast enough to take up the slack, there may be excessive drag on the strand because the pull of such succeeding traction roller will have to cause the strand to slip about both the second and third traction rollers 55 and 58.

Now the strand passes from the third traction roller 88 outside the water tank 58 and may, i! desired, pass over a grooved roller 59 having the same function as the grooved roller 5l, whence the strand enters a third tank 88 containing a preferably weak solution or bath of an alkali, for example ammonia 82, which may be at room temperature. A 5% solution is satisfactory, the purpose being to neutralize any free acid which the water may have failed to rinse off the strand. The strand now passes down into the ammonia solution 82 and under an immersed grooved roller 84 from which it runs in the ammonia bath and passes under another immersed grooved roller 86 and thence out of the solution. The strand then passes about a grooved roller 88 outside of the solution, and then about a fourth traction roller 00. geared to the roller 33 as at 43. The speed of the fourth traction roller 34 is preferably the same as or less than that of the thirdftraction roller 88, for the reasons noted above. with respect to the relation of the second traction roller 88 to the rst traction roller 22.

From the fourth traction roller 30 the strand may, if desired, pass over a grooved roller 82 having the same function as the grooved roller 31, and then passes into a fourth tank 34 containing a rinse bath of circulating water Il. which may be cold if desired, supplied as at 31 and discharged as at 93. The supply for both water tanks may be common, as by means of the pipe 83, and the discharge for both water tanks may be common, as by means of the pipe ill. The strand then passes under a grooved roller immersed in the water and moves along in the water, and, after passing under a second immersed grooved roller |02, departs from the water, passes about another grooved roller |03, and then over a fth traction roller |04. The speed of the fifth traction roller |04 is preferably the same as or somewhat greater than the speed of the third traction roller 8l.

The ammonia tank 30 may have a drain plug |05 arranged over the second water tank 34 from which the circulating water discharges to sewerage.

The vertical arrangement of tanks makes for compactness, small floor space requirements and eliminates rollers, which would be required, if the tanks were on the same level, to prevent the strands from touching the entering edge of the second and succeeding tanks. The staggered arrangement enables drainage from the traction rollers 55, 69 and 34 to drip into the next lower tank.

An idler roller |08, preferably of soft rubber, rests by gravity on the fifth traction roller |04 and cooperates therewith to form a wringer for removing excess but not all of the water adhering to the strand emerging from the second water tank 94, and also applies further traction. If the fifth traction roller |04 runs faster than the fourth traction roller 90 the fifth traction roller will slip past the strand, and the drag will not be excessive, due to the lowering of frictional resistance because of the wetness and the yieldability of the idler roller |06.

The strand emerging from between the traction and wringer rollers |04 and |86 has a core consisting at least in part of celluloslc material not affected or at any rate not substantially affected by the acid, covered by a gelatinous or gummy film or coat about which there is or may be a slight amount of moisture not removed by the wringing. The strand is then passed about a smooth grooved roller |03 and from there into a tank ||0 containing sodium silicate (water glass) ||2 or other coating material, preferably synthetic and preferably heat resistant, such as phenol formaldehyde. This tank is preferably rather deep and shaped so that the area at the surface of the silicate is small so as to minimize drying. Drying of the silicate may be further obviated by providing a removable lid ||4, having openings only for the entrance and departure of the strands. A grooved roller i8 immersed in the silicate solution ||2 guides the strands through the solution. The strand after passing under the grooved roller ||8 emerges from the sodium silicate solution and passes over another smooth grooved roller |20.

The strand then passes over sixth and seventh traction rollers |22 and |24 on which may rest 6 wringer rollers |28 and |28, all such rollers |24, |22, |24, |28 and |28 being removably supported in a steam or vapor chamber or box |28, for which an inlet pipe |30, connected to a suitable steam or vapor supply (not shown) may be provided. The box |29 may have a removable cover i3i. The rollers |22, |24. |28 and |28 in the chamber |29 serve to remove excess sodium silicate from the strand, while leaving a film of the silicate thereon, and prevent slackening of the strand between them and the fifth traction roller |04. Either or both of the gravity rollers |28 and |23 may be omitted, according to conditions. Each provides additional traction and wrings some of the silicate off the strand. The seventh traction roller |24, with or without the superimposed roller |28, prevents the tacky silicate coating from causing the strand to wrap around the sixth traction roller |22. The seventh traction roller |24 preferably runs as fast as the fth traction roller |04 or faster. The sixth traction roller |22 may run slower, as fast as or faster than the fifth traction roller |04 but not faster than the seventh roller |24. If the sixth traction roller |22 runs slower than the seventh traction roller |24, the strand will Aof course slip. Thereafter the ystrand passes over a grooved whipping wheel |32 from which it gravitates toward an endless conveyor belt |34, preferably waxed to prevent the silicate coated strand from adhering to the belt.

The traction and gravity wringer rollers are preferably made of soft rubber, synthetic or otherwise. The various traction rollers may be suitably driven, as by chain and sprocket, or by belt and pulley, although the grooved rollers associated and cooperating with traction rollers are preferably geared thereto. These grooved rollers could be friction-driven by the respective traction rollers, but this may be undesirable because if a strand creeps cut of a groove and enters between frictionally engaged portions of a grooved roller and a, traction roller, the strand will be bound and unable to slip, rendering it likely to break. A suitable arrangement is shown in Fig. 6. for example.

The chamber |29 is provided to furnish a moist atmosphere of steam or other vapor, hot or cold, which condenses on the silicate coat, the rollers |20, |22, |24, |28, |28 and the whipping wheel |32, so that the silicate on the strand and said rollers and wheel will not cause the strand to adhere to the rollers and wheel and also so as to prevent too rapid drying of the silicate on the strand. The moisture also dilutes the silicate on said rollers and wheel so that the diluted silicate drains off, thus cleaning the rollers and wheel. A baiile |36 provided on the box |29 prevents the draining diluted silicate from draining into the silicate tank ||0 and guides Vit into a suitable drain or container |38.

The purpose of the Whipping wheel |32 is to prevent the strand from wrapping about the next preceding (seventh) traction roller |24 and about itself. If the wheel |32 were circumferentially continuous, as are the rollers, then the strand, due to the fact that it is wet, would wrap about the wheel and not drop onto the conveyor |34. Therefore the wheel |32 has circumferentially spaced strand-engaging parts, such as the blades |33, formed with strand-guiding and separating grooves or notches |40. However, if the surface speed of the strand-engagmg portions of the blades were no greater than that of the seventh traction roller |24, then, due to the resulting relatively small amount of contact between the whipping Wheel |32 and the strand, the wheel would exert a relatively small amount oi traction on the strand, insuillcient to prevent the strand from wrapping about the traction roller |24. To overcome this drawback, I rotate the whipping wheel |32 at such a rate that the notches |40 of the wheel move at a substantially greater speed than, and hence slip relative to, the strand engaging the same while exerting a substantial tractive and whipping force thereon, sufficient to pull the strand taut from the next preceding traction roller |24. A speed ratio of about 3 to l has been found satisfactory but the ratio may be increased or decreased as desired. Six blades |30 equally spaced have been found satisfactory, but the number .may be smaller or greater as desired. The blades are preferably quite thin to ail'ord relatively small surface engagement with the strands. and each strand-engaging surface of the blades is smooth and rounded to avoid excessive traction and obviate snagging of the strand.

Due to the whipping action, the strand assumes a substantially curved shape about the whipping v wheel |32, as shown at |42, and drops from the wheel onto the conveyor belt |34. The conveyor belt |34 is preferably made of screening or perforated sheet material or any other material, metal or otherwise, which will allow the passage of air therethrough, and its outer surface is coated with wax, parailln or similar material to which the moist strand is non-adherent. The conveyor belt |34 may be mounted on suitable drums or rolls |44. Between the upper and lower runs of the conveyor belt |34, I provide a chamber |46 perforated as at |48 atthe top thereof to discharge cool or room temperature dry air which is delivered thereto as by a fan or from a source of compressed air (not shown). This dry air passes through the upper run of the conveyor belt and into contact with the strand. The air is dry for the purpose of drying the silicate nlm on the strand, and is cool in order not to soften the wax or like coat on the conveyor belt. The air is preferably blown with substantial force so as to raise th strand, as shown at |52. enough to allow the entire surface oi' the strand to come in contact with the air so that the drying of the strand will be circumferentiaily uniform.

The conveyor belt is preferably run at substantially less speed than that at which the strands 2|v drop from the whipping wheel |32 so that the strands will accumulate on the conveyor belt, rather than string out in a straight line, although the speeds may be substantially synchronized if accumulation is not desired.

` When the strand accumulates, it naturally forms into curls, as shown at |54, which lie in substantially horizontal planes dat over the conveyor belt, and has substantially the appearance. along the conveyor, of a continuous penmanship exercise oi' the letter 0, written according to the Palmer method, the spacing oi' consecutive turns grncoils depending on the relative speed of the It is desired that upon being discharged from the conveyor belt |34 the strand should be substantially non-tacky, yet suillciently soft so that 'I'he primary speed factor, however, is that of the strand in the acid tank 33. l

From the conveyor belt |34, the strand passes between crimp rollers |58 and |33, one roller being adjustable toward and awayi from the other. to provide between the cooperating teeth thereof ample space for the reception and crimping of the strand. If the conveyor belt is run at such a speed that the strand is substantially straight or at least uncoiled, on the conveyor, substantially only the thickness of the strand need separate the teeth of the crimp rollers. However, if the strand has been allowed to accumulate, i. e. curl, on the conveyor. the strand has one or more portions lying one on top of the other or others, and, when there are two or more strands, neighboring strands, if sunlciently close, will overlap, with the result that two or more strand thicknesses must be accommodated between the crimp rollers and hence the spacing must be correspondingly greater. 'I'he crimp rollers are preferably driven `by means of gears i60 which will be more or less tightly meshed according as the spacing ci the crimp rollers is less or, greater. Adjustment may be e'ected in any suitable ,mam ner. The strand upon discharge from the crimp rollers has the shape it had upon entering the crimp rollers, modiiied by the corrugating imparted to it by the crimp rollers. At this time the strand is non-tacky but still somewhat soft. When operating on strands treated as above described, the crimp rollers are preferably unbeated, l. e., at room temperature, for example, since heating will unduly harden the silicate coat and then the rollers will crack the coat and pulverize the coat at the cracks. 'I'he powdering is undesirable, since it will clog the crimp rollers and necessitate cleaning of adjacent parts. as well as the strand itself, especially when the strand is to be used as a filter in an air cleaner, for example. The crimp rollers |66 and |58 should run at substantially the same or at a reduced surface or pitch speed relative to the rst conveyor belt |34 in order to preclude pulling the strands, i. e., causing the strands to slide oil! the conveyor belt. From time to at the ilrst meshing teeth,

be drawn in and makes for a more able ilnal product.

The strand thus crimped is preferably baked. To this end it passes from the crimp rollers onto a second conveyor belt |80. This conveyor belt is disposed below the place at which the strand is discharged from the crimp rollers, but preferably as close as practicable. The reason for this is that if the corrugated strand were to have a long descent, it might tend by its own weight to straighten and thus nullify, at least in part, the eilect of the crimp rollers and of the curling and twisting which occurred when the strand was deposited on the first conveyor belt |34. A descent of about one inch to about four inches crimped. This snarled and therefore desir-f and weight of strand material.

The second conveyor belt ed on drums or rollers |82, and a heating means such as, for example, an electric hot plate |83, having a resistance wire |8311, or gas burner (not shown) is arranged to heat the upper run of the belt |80. The heat applied is such as to bake the entire strand dry, through and through, wit out injury. Of course the length of the belt |80 and the speed at which it is run are factors also. The belt should move no faster, and preferably moves slower, than the strands as they are deposited thereon from the crimp rollers |56 and |58. 1f the belt |80 should run faster, the strand would be pulled by the belt and thus tend to uncrlmp and uncurl. It may be best to bake the material slowly in order to insure that the surface of the strand is not excessively heated and thus lniured and to obtain substantially uniform drying throughout the thickness of the strand. The baking temperatures are readily ascertainable by trial and error, depending on the strand material. For example, an all-cotton thread treated as herein outlined has been found to turn out satisfactorily if, while at a temperature of about 300 F. for a period of about one minute. A thinner all-cotton thread of the same number of plies and twists and so treated should have a lower baking temperature to avoid excessive table and synthetic fibers treated as above may require still other baking temperatures, depending on their resistance to heat. The selected temperature in any event should not exceed and preferably should be below the lowest safe temperature of the strand in question.

Suitable provision may be made for controlling the temperature of the heater, as, for example, a rheostat |85 in the circuit of the heater resistance element peratures of, say, the upper run of the belt |80, together with an adjustable thermostat |86.

The baking step has a shrinking effect, causing the strand to permanently kink, as shown at |81, at relatively short and irregular intervals, on the order of about 1A" more or less to about 1" more or less, independently of and without otherwise substantially affecting the curling and crimping.

The baking step completes the process of making one form of filament |88 according to my invention. In this form the filament is highly resilient and flexible, with a hard, rough, friction surface film |89, an inner relatively soft sheath |90, and the core |9|, entirely or partly of cellulose, the filament being kinked as shown at |81 at irregular intervals, corrugated, and, if the strand is curled, or curled and twisted, on the first conveyor |34, the filament is also curled, or curled and twisted. If the filaments are allowed to drop from the baking conveyor |80, or from a roller ISI beyond the conveyor IBG, in a heap or pile |95 on a floor |98 orV other support, they will become snarled into a shapeless mass which can be pressed to desired shapes according to the use to which the filament material is to be put, and in such shapes the masses will be resilient and substantially shape-retaining. The interlocking of the interengaged portions of the filament is greatly enhanced by the shape and roughness imparted to the lament by the treatment described, and, once packed, there will be substantially no slipping or shifting of the engaged portions. Moreover, because of this treatment, the engaged portions will have substantially point, rather than line, contact, so that the material can be greatly compacted and yet have adequate air space or cells or pores so that dust will not clog it.

When pressed into a shape for use as a filter in an oil bath type carburetor air cleaner, for examin motion. it is baked heating. Mixtures of vege- IBM and graduated to temple, my filament material is highly efficient. One reason for its etllciency is the fact that it is curled, corrugated, kinked and rough-surfaced, the surface including tiny projections and valleys resembling, to the touch, minute serrations. By reason of the surface roughness, the oil clings to the ridges and valleys, and, by reason of the curling, crimping and kinklng, the number of intersections. to which the oil also clings, is increased so that the oil encounters considerable resistance to flow up in the filter. Thus for a given oil bath air cleaner. the maximum amount of air free of oil and solids that can be drawn through the filter compares favorably with that which obtains when hair, wire and other conventional filter material is used. In addition to increasing the resistance to the rise of the oil. the roughness of the filament surface offers a longer path of contact with the air, so that more solids have an opportunity to be caught and retained than would be the case if the filament were smooth. Moreover, where the oil does not happen to cling to the filament, the roughness of the bare filament itself offers places for hooking and catching and retaining solids from the air. The curling, crimping and kinking augment these desirable effects.

A filter made of this material, also, -by reason of the fact that it is curled, crimped. kinked and rough surfaced, retains the oil for a longer period than other filter materials, a result which is important because oftentimes the idling speed of an engine is so low as to be insumcient to draw the air with a high enough force to raise the oil from the oil bath up into the filter to a sufficient extent to have any substantial air filtering effect. Moreover, owing to its resilience and shaperetaining property, such filter will not pack or mat down after a considerable period of' use, so that the air passages remain fully open indefinitely and thus not only permit the air to be drawn therethrough readily -but also enable the oil and solids to be readily and thoroughly washed from the filter. The filter can be made from one or more continuous filaments which can be spun as on a spool to shape as they are discharged from the baking conveyor |80. whereas other material, such as hair and some fibers, because of their relatively short lengths, require more handling and operations to vproduce the final product. The resilience thus obtained is lacking in filters made with the short hairs ete. now available. Some of the short hairs and fibers become separated and pass out with the air, which oi' course cannot be tolerated.

Owing to the silicate coat, the filament produced as above described is capable of withstanding the high temperatures to which it is necessarily subjected when used, for example, as a filter in a carburetor air cleaner, due to the heat of the engine, or in connection with a hot air furnace. In an air conditioning system, where the lter is coated with a dust-catching liquid, such as oil, the high efiiciency of my material will be apparent from the above.

These filaments can be pressed into bats or can be used in loose or bulk form for heat insulation purposes. In loose or bulk form it is also useful as padding for upholstery and other purposes.

If desired, glass, mineral wool, asbestos fibers, ultra short hair such as hog hair, or other relatively short bers may be dropped from a suitable hopper 20B onto the first conveyor belt |34 substantially at 202, rearwardly of the place at which the strands 2| drop from the whipping wheel |32,

'75 so that as such fibers are carried along by the bers may be drawn ofi' by suction into a hood 286 or other means to be collected and reused if necessary in accordance the bers used.

The auxiliary hairs and bers are relatively bulk and resilience. so

cause of the surface In accordance with tion I may start with another form of my invena thermoplastic strand and corrugate it. One way of accomplishing this result is by crimping the strand. using heated crimp rollers. The crimp rollers |56 and |58 may be used, and for this purpose one or each crimp roller may be hollow, as shown at 288.

2|2. If desired. the strand, after leaving the crimp rollers |56 and |58, may be allowed to cool suiciently to retain the shape imparted thereto and be collected in a heap on the oor or be snarl and interlock, so that it will pack yet tend to retain its shape as long as it is below its softening temperature, and thus may serve usefully as a lter, padding and the like.

To render the corrugated thermoplastic material 2|2 even more elcient, I prefer to add a heating step which may be similar to the baking to cause the material, which will belt, to squirm and wriggle, and kink and form into miscellaneous relatively small curls, bends and knots, at irregular and close intervals of roughly t" more or less, as shown at 2I4. 'Ihese formations added to the corrugations l greatly increase the resilience and the tendency to snarl and interlock, and hence render filters, etc., made therefrom more eiiicient.

The temperatures of the crimp rollers |56 and |58 and the baking conveyor belt |88 will vary with the characteristics of the thermoplastic strand suiciently to enable be formed and remain therein. The temperature of the baking conveyor belt should be slightly below the melting point of the thermoplastic strand.

The apparatus may be driven by any suitable echanism. 228. for

the corrugations to pulley 238 on the same shaft with the pulley 228 operates through a belt 23| to drive a pulley 232 which, through the associated smaller pulley 234 and a belt 285. drives a pulley 236 on vthe same shaft with the rear drum |44 of the rear or drying conveyor |34. A smaller pulley 288 on the same shaft with the pulley 236 receives a belt shaft with the rear drum conveyor |88. The conveyor from the rear drum to the forward drum thereof. and a pulley 244 on the same shaft with said forward drum operates throughl a belt 246 to drive a pulley 254 on the same shaft with the crimp roller |56, which, by means of the gears |68, drives the crimp roller |58.

On the same shaft with the pulleys 228 and 238 is a third pulley 232 operating through a belt 268 to drive a pulley 262. On the same shaft with the pulley 262 is a second pulley (not shown) belt 266 to drive a pulley 268 which is on the same shaft with and therefore drives the fth traction roller |84. A second pulley 218 on the same shaft with the pulley 268 operates through a. belt 212 to drive a pulley 214 which is on the same shaft with and therefore drives the third traction roller 66. A second pulley 216 on the same shaft with the pulley 214 operates through a crossed belt 218 to drive a pulley 288 which is on the same shaft with and therefore rotates the rst traction roller 32.

A third pulley (not shown) on the same shaft with the pulley 262 operates through a crossed belt 286 to drive a pulley 288. 0n the same shaft with the pulley 288 is a second pulley (not shown) which operates through a belt 288 to drive a pulley 282 whereby the fourth traction roller 88 is driven. A second pulley 283 on the same shaft with the pulley 282 operates through a belt 284 to drive a pulley 286 whereby the second traction roller 55 is driven.

A fourth pulley 388 on the same shaft with the pulley 262 operates through a. belt 382 to drive a pulley 884 on the same shaft with a second pulley 386 operating through a belt 888 to drive a pulley 8|8 on the same shaft with and therefore driving the sixth traction roller |22. second pulley 3|2 onV the same shaft with the pulley 3|8 operates through a a. pulley 8|8 on the same shaft fore driving the seventh traction roller |24.

l arranco i `13 v Athii'dpnlleynlcnthesameshaftwiththe pulleys #Il and Inl operates through.; belt I!! to` drive 'a pulley t!! on the same shaft with and therefore driving the whipping whcel- III.

Whilethereisshownanddescribedherein art'that various modieaiicns and rearrangements oi' the A ing from the spirit and scope of the invention.

lng-means for .the a strand containing cellulose witiisuiiuric acid topender tiresome geiaiincuameans for coating specific stnmtureembodrius the invcntion. it will he manifest to those skilled in the` parts may be made without depart l andthattliiesameisnotliinitedtothieparticularA 'forms herein disclosed. except insofar as indicated by the appended claims.

I clalmf 1. A process or making a irinxyillament. ccmprisingthestepsoftakingacellulosestraiimmersin's said strand in a bath of sulfuric acid solution, removing said strand when' it has acquired a gelatinous outer layerrbut before tbe core of said strandy has been substantially treated by said ,acid solution. rinsing said gelatinous coated strand in water until the `sii-ine is substanonly free of aus, immersmg said-strane umreafter in a bath of weak ammonia solution to neutralize any acid remaining on said strand after the water rinse. rinsing said strand there after in water until the ammonia is washed oli, g

then removing. excess liquid from said sirene,

' spaced blades having' circumferentially thereafter immer-sing said strand in a bath of taining cellulose with-sulfuric acid to render the exterior of the strand gelatinouameans for removing excess liquid from the gelatinous coat, means for thereafter lapplying a mm ol'sodlum silicate to said coat. means for thereaiter removing excess sodium silicate from said nlm, means for thereaiter applying moisture tosaid strand, means for intermittently subjecting successive portions oi said strand, while maintained in vmuistsneci condition, to a combined slipping and pulling action, a conveyor on' which the strand is then allowed to drop. means hfor drying said strand, while on the conveyor. to a moldable non-tacky state. means operable upon said strand after said strand leaves said conveyor and while said strand is in a mpidahle non-tacky state for crimping said strand, a second conveyor disposed closely adjacent said crimping means and on which the crimped strand from said crimping means. means forl maintaining said second conveyor at a temperature in the neighborhood o! 200 F., more or less. for baking saidstrand to a dry, relatively hard, resilient. kinky and crimped filament.

3. An apparatus for making s. strand into a kinky relatively stili resilient filament, comprising means for treating the exterior portion oi a strand containing cellulose with sulfuric acid to render the same gelatinous, means for coating said-gelatinous portion with a nlm of sodium silicate, means for ceiling the strand so coated,

a conveyor for receiving the coiled strand, means for baking the nlm-covered strand, said conveyor being operative to deliver the strand to said baking means. and means ior preventing the nlm from adhering to said conveying means A i. An apparatus ior making a'strand into a i5 ins-excess sodium silicate from said dim. means r lnous cdatedstrandinwateruntilthe same'is' substantially tree of acid, immersing said strand -renderhigthe of the strand, and means forrota saidfgelatinoiu portion with onlin ci sodium I Silicon. means for baking thsillm-c.

means for,conveying-the stranddio said baking means,- means for 'preveutinsthe ilinifrom adharing to said conveying means. and ,meansfor strand iron-tacky. said conveying meansinoludingmeans tor the strand while the strand is still in a moldable state.

6. An apparatus for conveying a' plastic strand having s. tacky surface. comprising a roller for feeding such a strand; end a rotary member toward which the strand proceeds from said i said rotary member having circumierenagglle notches for receiving and guiding the fed portion ting said member so that the strand-engaging portions of said notches move in the same direction as and substantially more rapidly than the engagedportions ot the strand. whereby said strand-engem por.- tions engage successiveportions ci `tluVstraiid intermittently and with a wipingvactlon so as to whip the strand and preventthe strand from wrapping about-saidroller and'about said rotary memher.i.g j 6. A prccessotniaxinga kinky filament. comprising uwstepaortakinga strand containing cellulose, md

dstrandwhsn .ii has acquired s Outeilmr.- but before the com or salu .been substantially treatedby said acid solu'tid'n'; rinsing said gelat-V thereafter in a bath of weakammonia solution to neutralize any acid remaining on said strand after the water rinse, rinsing said strand rthereafter in water until the ammonia is washed oil. then removing excess liquid from, said strand, thereafter immersins said strand in a bath o! sodium silicate until it has acquired' a hlm of said sodium silicate. moistening said liii. collins the lament while said dim is moist. partially drying permanently kink the strand.

' 7. 'An apparatus for forming a coiled iilainent.

comprising means for treating a strand containing cellulose with sulfuric acid torender the 'exterior, only, oi the strand gelatinous-l means for removing excess liquid trom the gelatinuous coat, means for thereafter applying a nlm oi'sodium silicate to said coat. means for thereafter removing excess sodium silicate fromsaid nlm, means for moving said strand from the last-mentioned removing' means, means affording anatmosplicre of steam for saidstrand and moving means. and means lorintermittently subjecting sucesslve portions of said strand in said atmosphere to a combined slipping and pulling action, whereby said strand. upon thereafter being deposited on a support. iorms'lnto coils.

8. An apparatus for forming a coiled illament, comprising means for treating a strand containing cellulose with sulfuric acid to render the exterior, only. of the strand gelatinuous. means for removing excess liquid from the gelatinuous coat. means for thereafter applying a iilm-oi sodium silicate to said coat, means for thereafter removnidetnnewhikennideenveyex-.toemeldehle lo UNI'IIDBTAM PATENTS A nomekyememmemopenbleuponnld Number um me :vendetta-num 0,303 meer -.......f Ang. 10.1851

lwhilemillslzmmiisinemoldmhlelien-keksStelle 119301 .--.....'Hayl,185'i torcrhnninseeidainnd. "8031i muuu-...Benutzen 9,' An mumble for mninc e coiled nement. x5, 81,261' Schmidt Jan. 15, 1001' meen me treaties e streng #minln- 101,601 Hudson Sqn. l?, 1870 lne cellulose vmnmlmrle edd le render the er 183,101 mhheeek Nov. i8. m2 terror, enla-.ot the :tram: teletlnoua, meen; 2er 075,117 Stocker Hay 2l, 180; removing exeeas liquid n'em the gentinoue cnet. 'im H111 Jul: 22, 1002 111m el sodium zo '191,000 hedenburgh -...1... June 6. 1000 silicate to said met. :new: fer thereafter renwv- 951.068' Wessel Mer. 15. i910 ing excess sodium lilioo from eeid 111m, means 1,236,400 Momma Aug. 14, i917 fer moving said mend from the lest-mentioned, 1,130,950 llaman Aug', x4, 1911 disposed .closely adjacent said orlmplnz means 2,155,007

removm means. menus aim-dine en mannen 1.260.340- .vaneemm een.-- June u, me oxsteam tor salem-emmene murine. menu. u 1.880.224` Beamten: Nenas, m0 means for intermittently subieetmc successive 1.609.930 llaseuu'......,. Bent, 30,1024 neu-tions of seid mand in said atmosphere to e 1,530,300 O'Een. Apr. 28, 1025 combined elimine and pulling action. 1,055,005 lI'.......- Oct. e, 1025 said strand. non thereafter being deposited on e 1,510,749 muy m, a, um support. tex-meinte coils. e crvw en which 30. 1.629.241 Ubbelomle Mey 1?, 192'! the strana leuzen to drop. means toev 4 1.600.003 Badmu- Apr. 17. 192s dryine md strand. while en said conveyor. to e 2,033,030 Drieooll Mar. 1?;1936 moldeble-nun-tneky mi. means Operable umn 2,046,741 Heberleiu -.----n. July l', 1836 am mand ener seid sh'end leaves said conveyor 2.070.133 Tevion- May 4, 1011'1A and while said strand is in a mnldeble nontecky 35 2,097,301 Q 193':

Nov. stehe for crimlins seid strand. e levend convertir 2.124.570 stel. July 2G, 1888 Ubbloh d. Avr. 1 193e and on whieh the crimped strand descends trom 2,174,634 Ehipp Out. 88: 1939 and erimniuz menne. endmumtor bakinzlid- 3,200,633 Dreyfus J 23, 1040 mend to e dry relmvely here, resilient. 'kinky 4o- 2.210,1f ATeam:- gebt. 1. 1940 and crimped mement. 2,380,2134 Blum Peb. 4, 1941 10. L limoen of meting a lement. eolnmieln: 2,253,140 8pm Aug. 19, 1941 the m01 tekins e thread containing cellulose. ,2.201.088 Non 4, 1041 the extenor'nortien. only. ot said thread 2,274,384 v hb. 31, 1942 meeting with surturn; me selutionnntli :ein exterior porl4,5 2,320,174 Rutiehem Aus. 10, 1w

tion is zeletlnieeeoetlns said sgatinled portion 2,833.2 Tmeede'll Nov. 2. 1w

with e. nlm whioh.. dry, hee Naislaent.

ou rement. resuena. me vermin repellent. me mm um Mensthethread. thethreadwhueitia Nmher Country Date moist, eorrugatlncthe veiled thread while thelm w 5,718. Greetyihln 1881 la etiu moist. beting the thread until dry to there- 108,432 Greet Jen'. 25. 1011 Britain by permenentlyset the 0011s and museum and 218.358 Geest Brltein Apr. a. 1921 Certificate of Correction Patent No. 2,470,039. May 10, 1949.

EDWARD E. LOVIG It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction es follows:

Col. 16, line 31, list of references cited, for the patent number 1,660,083 read 1,666,083

and that the said Letters Patent should be read with this correction therein that the seme may conform to the record of the case in the Patent Oice. Signed and sealed this 18th day of October, A. D. 1949.

THOMAS F. MURPHY,

Assistant Uommissz'oner of Patents. 

